dhcpperf is a DHCP load testing tool.Continue reading “Testing a DHCP server with dhcpperf”
innodb_flush_method defines the method for flushing data from RAM to disk.Continue reading “How to change innodb_flush_method in MySQL”
Once I discovered on the graphs a large burst of Multicast packets on one of the ports of the Cisco Nexus 3064 switch, while the CPU load increased to 30%, before that it was 12% with L2 traffic of 13 Gbit/s.Continue reading “High CPU load on Cisco Nexus 3064”
Once I created a raid, mounted it as a disk system partition and transferred the MySQL directory directly to it, but in this case there were drawbacks, the lost+found directory could appear, it could not be used for other data, etc., after that I began to transfer the MySQL directory not directly to the partition, but created a directory on it and transferred it to it.Continue reading “Migrating MySQL Directory”
innodb_io_capacity – determines the number of write IOPS for background InnoDB tasks, such as flushing pages from a buffer pool, etc. If the cleanup operation is lagging, then InnoDB can perform cleanup more aggressively at a higher IOPS, which is defined in the innodb_io_capacity_max variable.Continue reading “How to change innodb_io_capacity in MySQL”
I will give an example of installing and configuring xt_NAT on Ubuntu Server 14.04 with kernel version 4.4.0-142. xt_NAT may not work on newer kernel versions. According to the developer, it should work on Linux Kernel 3.18 and 4.1. To make it work on newer versions of the kernel, you can find patches.Continue reading “Installing and configuring xt_NAT”
Partitioning tables in MySQL is splitting a large table into parts according to the specified criteria, which will speed up reading and writing data to it if this table contains a very large amount of data.Continue reading “Partitioning tables in MySQL”
innodb_stats_on_metadata – Lets you collect statistics on metadata operations such as SHOW TABLE STATUS when accessing INFORMATION_SCHEMA.TABLES or INFORMATION_SCHEMA.STATISTICS tables.
In newer versions of MySQL, the innodb_stats_on_metadata parameter is disabled by default, which makes working with these tables faster.
thread_cache_size – responsible for caching client threads after they are disconnected so that they can be reused, for example, when hundreds of connections are made to the server per second, this parameter can greatly improve performance.Continue reading “Changing thread_cache_size in MySQL”
Default value is 1, possible values are 0-2.
0 – Logs are written and flushed to disk once per second. Transactions that have not been flushed out can be lost as a result of a crash.
1 – Logs are written and flushed to disk every time a transaction is committed.
2 – Logs are written after each commit of a transaction and flushed to disk once per second. Transactions that have not been flushed out can be lost in the event of a failure.